Al Qaeda leader Osama bin Laden convened a huge 'terror summit' in Afghanistan shortly after the collapse of the Saddam Hussein regime in Iraq, in which he outlined plans to launch 'unbelievable' attacks using biological weapons, according to Taliban officials.

At the meeting held in a mountain stronghold in April, bin Laden said he was working on 'serious projects', Taliban officials in Pakistan and Afghanistan were quoted as saying in the latest issue of Newsweek magazine.

"His priority is to use biological weapons," a source who claimed that Al Qaeda already has such weapons, was quoted as saying.

The source insisted he did not know any further details like how these would be transported, but bragged, "Osama's next step will be unbelievable."

The plan, however, was reportedly delayed and revised after the capture of Al Qaeda's operations chief Khalid Shaikh Mohammed in Rawalpindi in March, the report said.

US intelligence officials were quoted as saying that no one disputed bin Laden's interest in germ warfare.

Nevertheless, they argued, his main priority was to kill Americans by any means readily at hand -- and most bioweapons are harder to get and use than many of the alternatives.

Two years after the September 11 attacks, the world's most wanted terrorist remains free.

"We don't know where he is," US Army Colonel Rodney Davis, spokesman for US forces in Afghanistan, told Newsweek. "And frankly, it's not about him. We'll continue to focus on killing, capturing and denying sanctuary to any anti-coalition forces, whether they are influenced by bin Laden or not."